1. Field of the Invention
The present invention relates to a manufacturing method of a molded multilayer article such as a door trim board or an interior material of automotive vehicles, an interior or exterior material of houses, etc., and more particularly to a manufacturing method of a molded multilayer article the outer surface of which has a soft feeling.
2. Technical Background of the Invention
As a molded multilayer article described above, there is a door trim board of an automotive vehicle which is composed of a base member of wooden material or synthetic resin material formed in a predetermined shape and covered with a skin material through a foamed intermediate layer.
During a manufacturing process of the door trim board, as shown in FIG. 15, an adhesive is sprayed on the surface of a porous wooden base member 1 and once dried. Thereafter, the porous wooden base member 1 is placed on a vacuum molding die 5, and a skin material 2 composed of a skin layer 2b of soft synthetic resin formed in a sheet and backed with a foamed soft layer 2a is retained by a support frame 3 at its outer periphery. The skin material 2 is moved down after softened by a far infrared rays heater and placed of the base member 1 and an upper peripheral portion of the vacuum molding die 5. In such a condition, a suction passage 6 and its branch passages 6a in the molding die 5 are applied with negative pressure from a vacuum source 7. Thus, the skin material 2 is sucked by the negative pressure applied from the branch passages 6a through the porous base member 1 and is adhered to the whole surface of base member 1. After being removed from the molding die 5, the skin material 2 adhered to the base member 1 is cut out in such a manner that an outer periphery of the skin material 2 is protruded out of the base member 1. The protruded outer peripheral portion of the skin material 2 is rolled inwardly and adhered to the outer periphery of the base member 1 to complete the door trim board.
Since in such a conventional manufacturing process, an adhesive is used to adhere the skin material 2 to the base member 1, the working environment is injurious to health and the working process is complicated. To solve such problems, there has been proposed a manufacturing method of the door trim board comprising the steps of setting a skin material backed with a foamed layer on a molding die, melting synthetic resin supplied into the molding die and compressing the melted synthetic resin to form a base member covered with the skin material. Although such a manufacturing method is useful to improve the working environment and to simplify the working process, the skin material is damaged by heat and pressure during the mold process of the base member, and the appearance of tile skin material is spoiled by, unevenness of the molded surface of the skin material, pockmarks or the like.
In any case of the conventional manufacturing methods, it is, however, required to install a molding machine and an adhesion device for preliminarily preparing a skin material composed of a skin layer backed with a foamed layer. Since after the molding process, the processes for trimming the outer periphery of the skin material, for inwardly rolling the outer periphery of the skin material and adhering the same to the outer periphery of the base member are required, the manufacturing cost of the door trim board is increased due to requirement of the devices for the foregoing processes. Since in addition, the skin material is retained on the molding die at its outer periphery in such a manner as to fully cover the base member, the skin material must be prepared in a large size for trimming. This causes a large amount of useless remainders of the skin material.